1. Field of the Invention
This invention relates to leather splitting equipment for animal hides, and especially to an automatic retraction system for a ring roller to facilitate cleansing of the ring jaw insert(s) via automatic retraction of the ring roller.
2. Description of the Prior Art
FIG. 1 is a cross-sectional view of a typical band knife splitting machine 1. The hide 3 to be split is laid out manually on the infeed table 2 and is fed towards the rotating rollers, which in turn grip the hide and lead it towards the rotating band knife 4. The vertical gap between the upper feed roller 5xe2x80x94or xe2x80x9cgauge rollerxe2x80x9dxe2x80x94and the knife edge determines the thickness of the top split 7. This relationship implies that the top split (xe2x80x9cgrainxe2x80x9d) must have a uniform thickness while the xe2x80x9cfleshxe2x80x9d split 8 issuing from below the knife edge will exhibit those differences in hide thickness that are determined by nature.
In order to achieve uniform grain thickness the lower feed roller 6xe2x80x94or xe2x80x9cring rollerxe2x80x9d xe2x80x94has to have a resilient mounting and be capable of deviating from the straight line of its rotation axis. The ring roller, composed of a set of individual section rings arranged on a shaft, rests on the rubber roller 9.
The vertical surface of the scraper plate 10xe2x80x94or xe2x80x9cring jaw platexe2x80x9dxe2x80x94ensures that the section rings can only give way at right angles to the knife edge. A replaceable insert 11 with sharp beveled edge installed on the tip of the ring jaw plate is designed to scrape off the flesh split from the ring roller and prevent the flesh split from xe2x80x98wrapping aroundxe2x80x99 the ring roller.
The flesh and grease particles scraped off the flesh side of hide during normal splitting production accumulate at point of contact between the ring jaw insert edge and ring roller (FIG. 2). However, the accumulation of this debris, including flesh and grease particles, interferes with proper centerline position of ring roller with gauge roller. Flesh and grease particle accumulation at the ring jaw insert edge causes individual section rings to deviate from their center of rotation axis and forces the individual section rings upwards into the traveling band knife. Therefore, the debris at the ring jaw insert edge must be removed periodically to maintain splitting accuracy.
Splitting machine operators can successfully remove debris by reversing ring roller rotation (FIG. 3). The ring roller rotating in the opposite direction forces loose flesh and grease particles away from the point of contact between the ring jaw insert edge and ring roller. The ring roller moves into proper working position and rotates smoothly when all loose debris is dislodged from the ring jaw insert edge.
Unfortunately, sufficient removal of debris from the ring jaw insert edge via reversal of ring roller rotation often proves unsuccessful (FIG. 4). In such cases, splitting machine operators stop production and turn off the splitting machine feeding system. For safety purposes, the operators stop band knife rotation and also retract the band knife. The operators retract the splitting machine infeed table to expose the entire ring roller (FIG. 5). The operators then remove the ring roller from the splitting machine to gain access to the ring jaw insert edge. Two or three operators remove the ring roller to prevent deformation and excessive bending of the ring roller shaft. Since the ring roller is situated in an area of very limited and hazardous working spacexe2x80x94directly in front of the razor sharp band knife edge (FIG. 6), which wraps around a first pulley 12 and a second pulley 13xe2x80x94operators frequently use safety hooks 14 to pull the ring roller out from the splitting machine. The machine operators clean the exposed ring jaw insert edge with a tool 15 made from wood or plastic material (FIGS. 7 and 8) and then manually reinstall the complete ring roller.
Splitting machine operators and maintenance personnel are exposed to a specific personal safety hazard when manually removing and reinstalling the ring roller: hands and fingers always come into close distance with the razor sharp traveling band knife. Personal safety is compromised further by existing working conditions:
1) wet and greasy floor space
2) wet and greasy equipment and machinery
3) wet and greasy hides for splitting
The machine operator can lose physical balance in this wet and greasy working environment. Therefore, during ring roller removal or reinstallation, the machine operator is exposed to great risk of personal physical harm via accidental contact with the razor sharp traveling band knife.
The personal safety of splitting machine operators is further compromised in high production working environmentsxe2x80x94i.e. splitting 200 to 300 hides per hour. To meet these stringent production requirements splitting machine operators must minimize the total time required to properly pull out the ring roller, clean the ring jaw insert edge and correctly reinstall the ring roller.
Splitting machine operators are usually not certified mechanics or engineers, having extra training in mechanical or engineering matters. Therefore, the ring roller removal and reinstallation procedure also possibly increases the possibility of mechanical damage to the ring roller.
In view of the preceding, it is an object of the invention to provide a hide splitting machine having a system for automated retraction of the ring roller assembly.
The ideal system for retracting the ring roller assembly has the following features:
1. Facilitates access to ring jaw insert edge.
2. Minimizes cleaning time of ring jaw insert edge to maximize frequency of debris removal from ring jaw insert edge.
3. Minimizes risk of personal injury.
4. Minimizes risk of ring roller mechanical damage.
5. Minimizes machine operator""s required level of technical expertise.
In the invention, a hide splitting machine is used, the machine comprising an in-feed table, a ring roller, a rubber roller to support said ring roller, a gauge roller and a traveling band knife. The machine is arranged to split hides fed into a gap created between the ring roller and the gauge roller. The ring roller is rotatably held in a pair of swivel arms, the swivel arms being anchored at outer ends of a first pivot arm and a second pivot arm. The first pivot arm and the second pivot arm are arranged co-axially with the rubber roller, with the first pivot arm arranged at one end of the rubber roller and the second pivot arm being arranged at the opposite end of the rubber roller. The first pivot arm is pivotable using a first biasing means and the second pivot arm is pivotable using a second biasing means. When said in-feed table is swung away from the rubber roller, the first and second pivoting means, respectively, can be pivoted away from the gauge roller moving the ring roller also away from the gauge roller.
Advantageously, the first and second biasing means comprise linear actuators, for example pneumatic cylinders, hydraulic cylinders, long-throw solenoids, gear-driven actuators or mechanical linkage systems.